A photosensitive composition contains a polymerizable compound having an ethylenically unsaturated bond and a photopolymerization initiator. A photosensitive composition polymerizes to cure on being irradiated with energy rays (light) and is used in photo-curing inks, photosensitive printing plate precursors, various photoresists, and the like.
Patent documents 1 to 3 listed below propose using an oxime ester compound as a photopolytnerization initiator of a photosensitive composition. However, the oxime ester compounds disclosed do not have satisfactory sensitivity.
A colored alkali-developable photosensitive resin composition containing a colorant for use as, for example, color filters is required to have high sensitivity. Therefore, a photoresist should have a high concentration of a photopolymerization initiator. However, a photopolymerization initiator of high concentration has raised problems, such as poor developability that causes scum or undeveloped residue formation and contamination of a photomask or a heating oven by sublimate.